This invention relates to fire and security alarm systems and more particularly to a wireless residential fire and security alarm system.
Currently available wireless home fire and security alarm systems are usually part of a so-called wireless security system that requires a hardwired keypad, a base station, a hardwired siren, AC power connections, and an autodialer connection to a telephone line if the system is to be monitored. Such wireless systems actually require, therefore, considerable wiring, which makes them expensive to install and requires skilled installers.
In an effort to reduce costs and wiring, some prior workers have combined the keypad and the control panel into a single unit. However, this combination is bulky and inconvenient for wall mounting, which is required for keypad access but which renders difficult the installation of AC power, telephone, and siren wiring.
Other prior workers, in an effort to reduce manufacturing and installation costs, have further combined the siren into the keypad and the base station. However, few professional alarm installation companies will use such equipment because its security is compromised. For example, an intruder, upon hearing the siren, could simply smash the siren/keypad/base station or forcibly remove it from the wall and the alarm system and telephone autodialer dialer would be disabled. Therefore at least the autodialer needs to be separate from the keypad or siren to maintain adequate security.
Smoke detectors are key sensors in a fire alarm system. In prior wireless alarm systems, the smoke detectors are battery operated and include a small transmitter that transmits a fire alarm message to the control panel. To sound the alarm throughout the house, the control panel triggers a siren. In the frequently occurring event of a false alarm, the homeowner must use the keypad to reset the alarm and go to the location of the detector that caused the false alarm to reset the detector or place it into a xe2x80x9chushxe2x80x9d mode.
Prior wireless sensors, such as intrusion sensors, transmit an alarm whenever they are tripped irrespective of whether the alarm system is armed. In kitchens and high traffic areas, such alarm transmissions can unnecessarily reduce the sensor battery life and can create signal contention problems when more than one sensor transmits at the same time. Reducing these unneeded transmissions would, therefore, be beneficial.
When the alarm system is armed and an actual alarm condition is detected, prior systems sound the alarm throughout the house with one or more sirens. Each siren requires a separate installation and is usually wired in, even in so-called wireless systems.
Because of the above-described limitation, prior wireless alarm systems are unduly complicated, especially for a typical homeowner to install or service, and do not have the benefits of typical hardwired systems. Accordingly, the full market potential of wireless home fire and security alarm systems has not been realized.
There are various U.S. patents that are potentially relevant to aspects of this invention. U.S. Pat. No. 4,363,031 for WIRELESS ALARM SYSTEM is described in the detailed description section of this application.
U.S. Pat. No. 5,686,885 describes sending a test signal along with an alarm signal from a smoke detector to differentiate a test event from an alarm condition.
U.S. Pat. No. 4,855,713 describes automatically xe2x80x9clearningxe2x80x9d the pre-assigned addresses in transmitters used for security systems.
U.S. Pat. No. 5,465,081 describes a wireless communication system that uses transceivers to communicate from one device to another in a loop configuration while modifying the message being sent around the loop to reduce the number of transmissions required during a supervision poll.
U.S. Pat. No. 5,486,812 describes a centralized locking system in which wireless transceivers are located in window and door locks to allow locking all doors and windows by a single transceiver based key fob button depression. If a door or window is open, the key fob is informed that complete locking cannot take place. This patent, like U.S. Pat. No. 5,465,081, describes a system in which messages are passed around a loop from one device to the next.
It is an object of this invention, therefore, to provide a low-cost, low-power, user installable, supervised alarm system that requires little or no wiring.
A wireless fire and security alarm system of this invention employs two-way transceivers in the smoke detectors, other sensors, and base station. The conventional keypad can be eliminated completely because the fire alarm system is reset by pressing a Test/Silence button built into every smoke detector or fire sensor and the security system is armed and disarmed by use of a wireless key fob sized transceiver. The separate siren is also eliminated because the siren in every smoke detector sounds an alarm throughout the building when any one of the smoke detectors detects a fire. This can be accomplished because every detector has a built-in transceiver and can, therefore, receive alarm messages from any other smoke alarm.
The AC power connection is also eliminated because the control unit is battery powered. Only a telephone wire connection is, therefore, needed for the system to be monitored. Moreover, in simple residential applications, the base station is not even needed unless centralized monitoring is required.
In multi-dwelling facilities such as apartments or college dormitories, smoke detectors in one dwelling space relay alarm conditions from dwelling space to dwelling space until reaching a centralized base station for the entire facility. This centralized base station can be located in facility manager""s office for immediate notification of an alarm, improper smoke detector operation, low or missing battery indications, and dirty smoke detector indications. Such a wireless alarm system can save many lives in apartments, where smoke detectors batteries are often depleted or removed.
Another embodiment incorporates a long range wireless base station that communicates over standard cellular, GSM, or PCS type networks so that not even a telephone line connection is needed.
Further enhancements include battery conserving communications protocols, a simpler means of identifying and locating trouble conditions, an alarm verification mode for false alarms reduction, simple sensor enrolling and removing methods, and voice annunciation of fire location.
Primary features and operating modes of this invention are described below.
Automatic device addressing (enrolling) eases the addition and removal of smoke detectors, intrusion sensors, or other devices (collectively xe2x80x9csensorsxe2x80x9d) from the alarm system. Programming is automatic, meaning that no address switches need to be set. No addresses need to be preprogrammed into device, and no address numbers need to be entered into the base station.
Enrollment is carried out by pressing an xe2x80x9cEnrollxe2x80x9d button on the base station, causing it to listen for new sensors. Inserting batteries into new sensors to be enrolled on the system causes the new sensor to send out a xe2x80x9cnew devicexe2x80x9d message. At this point, the sensor has no address, which marks it as a new device or one that has a previously defined xe2x80x9cnew devicexe2x80x9d message. Sensors, therefore, do not need to be uniquely preaddressed and can be generic from manufacturing. When the base station is in enroll mode and receives a new device message, the base station automatically enrolls the associated sensor into the system by downloading a house code address and a unit address to the new sensor. After the sensor is enrolled into the system, the sensor indicates enrollment by beeping its sounder, flashing its light-emitting diode (xe2x80x9cLEDxe2x80x9d), or otherwise indicating that enrollment has been accepted.
Because sensors might lose their assigned addresses when batteries become depleted and require replacement, the following procedure eliminates confusion and automates the process. Pressing the xe2x80x9cEnrollxe2x80x9d button on the base station causes the base station to poll all the sensors in the system to determine which of the sensors are currently enrolled and how they are currently programmed. Then, removing the batteries from one sensor at a time, and inserting new batteries into that xe2x80x9cnewxe2x80x9d sensor causes it to send the new device message because it has lost its addressing. When the base station receives the new device message, the base station initiates another poll of all sensors in the system. If one address is now missing, the base station assumes that the missing address is associated with the same sensor that is sending the new device message and then reloads the original address into the xe2x80x9cnewxe2x80x9d sensor. As before, the sensor either beeps or flashes to indicate enrollment.
There are instances when devices must be removed from the system, such as when a sensor fails. If the failed sensor is not un-enrolled, the system recognizes that the failed sensor is missing and generates a continuing xe2x80x9cRF Linkxe2x80x9d trouble message, until the failed sensor is repaired and returned to the system. When the Enroll mode is entered, the base station polls the system to determine which sensors are currently enrolled. Any nonresponding sensors are automatically removed from the current system status and are, therefore, no longer polled for supervision purposes and are unable to activate the system. In some cases, such as with security devices, to prevent unwanted tampering, entry of a security code may be required before a device can be removed from the system.
It is desirable to be able to reset a fire alarm system from any detector because false alarms are all too common. For example, cooking fumes, bathroom steam, or fireplace smoke can set off a smoke detector. In such cases, the homeowner would want to reset or silence the system as quickly as possible. U.S. Pat. No. 4,363,031 (the xe2x80x9c031 patentxe2x80x9d) describes an unsupervised system that can reset a wireless fire alarm system from any sensor. However, the system requires two buttons, one for test and one for reset.
An improved and supervised one-button process of this invention provides each sensor with a xe2x80x9cTest/Silencexe2x80x9d button. If the system is in its normal non-alarm state when this button is depressed, the sensor sends a xe2x80x9cTestxe2x80x9d signal that signals all the sensor sounders to sound for a predetermined time and signals the base station to dial a test message to the monitoring station (if the test messages in the system are to be monitored). If the system is in an alarm condition or a test alarm condition, then pressing the Test/Silence button causes a xe2x80x9cSilencexe2x80x9d signal to be sent to the other sensors and the base station to silence the sounders and reset the alarm system. If the Test/Silence button is depressed during an alarm condition but before a preprogrammed autodialer delay (usually about 15 seconds), the base station is prevented from autodialing an alarm condition to the monitoring station.
Problem identification is another important consideration. In prior wireless alarm systems, a sensor having a low battery chirps its sounder and sends a trouble signal to the base station, which displays a low-battery trouble signal along with the address number of the affected sensor. Some sensors may also indicate a xe2x80x9cdirty sensorxe2x80x9d or an xe2x80x9cout of sensitivity rangexe2x80x9d condition. As before, these sensors can chirp their sounders or flash LEDs, and send a message to the base station. If the sensor fails to properly communicate with the base station, in a supervised system the base station indicates a trouble condition and the address number of the affected unit. In an unsupervised system, a failure to communicate may not be detected by the system and will not, therefore, be reported.
The wireless alarm system of this invention overcomes these limitations because every sensor has a receiver and the system is supervised. When a low battery is detected by a sensor, instead of beeping, which is irritating when it occurs at night, a signal is sent to the base station, which sounds a quieter trouble sounder. Information regarding the nature of the trouble signal is retrieved by depressing a Diagnostic Mode button. A xe2x80x9cLow Battery Detectorxe2x80x9d LED illuminates and the base station transmits a message to the appropriate sensor to sound for a predetermined time, preferably about three minutes, to identify which sensor requires fresh batteries.
U.S. Pat. No. 5,686,896 describes sending a pre-low battery report from a sensor to a central station and using a timer to delay triggering a local xe2x80x9clow batteryxe2x80x9d alarm. The present invention, however, uses two different low battery thresholds and does not employ a preset time delay between the two different messages. Low battery signals may be sent to the base station for annunciation there rather than at the smoke detector, where it would be annoying. Locating the base station in a building manager""s office or at a remote monitoring station also prevents the annoying local low battery alarm that sometimes causes renters and home owners to remove batteries. The second threshold detects when the battery is at the very end of its life and sounds the local alarm only when the battery is nearly depleted.
If the problem is a dirty detector sensor, the base station illuminates a xe2x80x9cDetector Dirtyxe2x80x9d LED and transmits a signal to the affected sensor to sound.
If an alarm has occurred and the homeowner or the fire department needs to know which sensor originated the alarm, the same process can be used. When the base station is placed in Diagnostic Mode, a red xe2x80x9cAlarmxe2x80x9d LED flashes to indicate an alarm condition and sends a signal to the affected sensor to sound its sounder.
When a sensor ceases communicating with the system, it is difficult, if not impossible, to send the affected sensor a message to sound its sounder. Because the affected sensor has a transceiver, however, it can recognize that it has not been polled for a predetermined time and is unable to communicate with the system. The sensor responds by changing the flashing of its LED to a trouble pattern. This way, when the base station performs its normal hourly poll and discovers that a sensor is not responding, it illuminates an xe2x80x9cRF Linkxe2x80x9d trouble LED alerting the homeowner to inspect each of the sensors to determine which one has its LED blinking the trouble pattern.
The alarm system of this invention provides a homeowner an ability to quickly identify and manage problems. However, the system can also be programmed so that all system trouble messages are monitored by a remote monitoring station, in which case trouble signals will be sent via the dialer rather than displayed locally.
The Consumer Product Safety Commission and the National Fire Protection Association report that approximately 30 percent of all residential smoke detectors are not operational because their batteries are dead, have not been replaced, or have been removed. To avoid this problem, supervised alarm systems monitor the operational status of sensors. However, batteries are removed mainly because of frequently occurring nuisance alarms. The above-described ability to silence the system from any detector reduces this problem. However, in a monitored system that can automatically summon fire or police services, reducing the number of false alarms is vitally important.
A false alarm reduction method commonly used in hardwired systems is referred to as alarm verification. Alarm verification has not been previously employed in wireless systems because they did not include receivers in each sensor. While the above-mentioned ""031 patent describes a system capable of including a receiver in each smoke detector, it describes neither alarm verification nor system supervision capabilities. However, the alarm system of this invention provides the following alarm verification capability. When a sensor first generates an alarm signal, it sends an alarm message to the base station. If the base station is set to verify the alarm, it returns a reset message to the sensor. The base station starts a timer, and if that sensor or any other sensor in the system sends another alarm message within 60 seconds, the base station transmits a message to all sensors to sound their sounders.
There are significant benefits from having a fire alarm system in which all sensors sound when any one sensor detects an alarm condition. This feature, referred to as tandem operation, can provide up to four times more warning time in response to a fire alarm. For example, if a fire starts in a basement, a person asleep in a bedroom might not be alerted by his or her bedroom sensor sounder until it is too late to escape. For this reason, virtually all new construction codes since 1989 have required wired interconnected smoke alarm systems. Yet the vast majority of homes built prior to 1989 do not have such systems because of the wiring expense.
Prior wireless fire alarm systems that incorporate only transmitters in their sensors cannot receive messages to sound their sounders in the case of an alarm. Therefore an external siren is needed to sound a fire alarm throughout the house. The ""031 patent describes a smoke detector system that includes receivers, but its protocol does not supervise each sensor. This omission prevents detection of any sensor that loses communication with the system. Accordingly, unsupervised systems are considered unreliable for use in security systems, and are even less reliable for use in fire alarm systems. Therefore, a supervised system is desirable.
This invention includes a two-way wireless alarm system in which the sensor is addressable and, therefore, can be supervised and have its sounder commanded to sound. The two-way wireless system of this invention communicates either directly to the base station or by passing messages through other sensors to the base station.
A person awakened by a fire alarm is often in a state of confusion, which can cause deadly evacuation delays. Therefore, vocal annunciation of the fire detection location is employed to evoke an efficient and appropriate response. This invention includes a smoke detector with a speaker that plays prerecorded vocal messages on command. Switches set by the homeowner during installation select an appropriate message, such as identifying on which floor the detector is being installed. Accordingly, when a fire is detected by a smoke detector installed on the first floor, the smoke detector can transmit a message to all the other smoke detectors to repeat a prerecorded vocal message such as, xe2x80x9cFire on First Floor.xe2x80x9d
Another advantage of this invention is that apartment or dormitory systems do not need a base station in each residence. Because each sensor includes a transceiver, a base station is required only if the system requires centralized monitoring, in which case a single base station provides the autodialer or other communication means, such as a cellular radio link. In apartments or dormitories, where living areas are close together, the two-way wireless system communicates from one living area to the next. One of the sensors is designated as a master sensor that acts as a communications hub for other sensors in that residence. The master sensor includes control functions and supervision functions, but not necessarily the autodialer or other communication means. Alarm and polling messages are transmitted from the master sensor of one residence to the master sensor in another residence, on to the next residence, and finally onto a base station, which is preferably installed in a manager""s office. The base station provides the autodialer and other communications means, if monitoring is desired, or simply provides local monitoring.
This system supervises the operation of each sensor to ensure the sensors are properly powered, communicating, and not dirty. In one operational mode, a fire detected in a hallway can sound the sounders in the sensors in each residence on that floor. This alarm system provides superior monitoring and supervision of apartment and dormitory sensors and is considerably less expensive than prior systems because as few as one base station is required for an entire complex rather than one base station for each residence.
Some prior systems have tried combining the base station with the keypad, an arrangement that requires placing the keypad/base station in a central location close to telephone lines. However, the alarm system of this invention employs a supervised two-way wireless network that eliminates the need for hardwired sirens and a separate keypad. This invention allows resetting the fire alarm system from any sensor and, therefore, allows locating the base station close to existing telephone lines. Access to the base station is required only to review trouble conditions, as they arise. However, because the system can be monitored, it is possible for the monitoring center to manage these trouble problems, thus eliminating the need to display trouble conditions in the residence at all.
One embodiment of this invention employs a receiver that is enabled very briefly (one to two milliseconds every second) to reduce receiver electric current draw, thereby providing a battery life of many years. In an alternative embodiment, an ultra-low power xe2x80x9cwake-upxe2x80x9d receiver may be employed in each device to enable an asynchronous transceiver network that simplifies communications protocols and further reduces battery power requirements. Both embodiments eliminate the need for AC power wiring and the associated power supplies. The elimination of these extra wires simplifies and speeds installation, thereby enabling homeowners and relatively unskilled installers to install the systems. Improved fire protection is, therefore, practical in all homes including those built before 1989.
Another advantage of this invention is that all sensors sound an alarm even if a base station is damaged or non-operational. Possible causes include accidental damage, batteries depleted or removed, or wireless communications interference or blockage. In such instances, it is desirable for all sensors to sound an alarm if a fire is detected. This is possible in the alarm system of this invention because each sensor is able to confirm whether its alarm message has been received by the base station. If after repeated attempts, the base station fails to respond, the sensor automatically transmits its alarm message to the other sensors, which sound their sounders.
When prior panic buttons were pressed, the user could not be certain whether the panic message was received by the monitoring station. However, this invention may also include an emergency response button having an audible confirmation. This is possible because this invention can readily include a combination of sensor types each including built-in transceivers selected from among smoke detectors, security sensors, wireless two-way keypads, hand-held wireless key fobs, energy management devices, thermostats, meter readers, and wireless emergency panic buttons. However, the panic button of this invention includes a transceiver and a mini-sounder that beeps in response to an acknowledgment message received from the monitoring, station by way of the base station.
Additional objects and advantages of this invention will be apparent from the following detailed description of preferred embodiments thereof which proceed with reference to the accompanying drawings.